From the time they are born, children begin learning of the effects of friction and gravity upon motion. Even very young children appreciate that some effort is constantly needed to overcome friction if motion is to be maintained. When a toy with wheels is pushed, it soon comes to rest again.
Children also soon learn of the effects of gravity. An object that is not held quickly drops to the floor and objects that have wheels move much more easily along the floor than objects that do not have wheels. Object that hover or levitate are, therefore, very interesting to children because they defy the law of gravity.
Such fascination is not, of course, limited to children. Mankind remains concerned with efficient ways to overcome friction and gravity. Ever since the invention of primitive land vehicles, efforts have been made to reduce the friction associated with movement of vehicles, because friction wastes otherwise useful work. With watercraft, the emphasis is to reduce friction in the form of hydrodynamic drag, and with both land vehicles and watercraft at high speeds, there arises a need to reduce aerodynamic drag as well.
Thus, a toy that appears to simultaneously defy the laws of gravity and friction holds particular interest for children, and many adults as well. Moreover, such a toy can furnish an intriguing educational opportunity for everyone, and its study by engineers whould provide a model upon which to base future, substantially more efficient, ground and/or water transportation.